If one insulated rail joint becomes short-circuited, how many track signal circuits will be affected?

When an insulated rail joint becomes short-circuited, it disrupts the electrical isolation that the joint provides between different segments of the track signal circuit. Insulated rail joints are implemented in railway systems to prevent electrical current from flowing between adjacent track sections, which can each serve as separate signal circuits.

In a typical setup, each insulated rail joint is expected to isolate two separate track segments. Therefore, if one of these joints becomes short-circuited, it can effectively connect the two segments that were previously isolated. This can lead to the possibility of affecting the signaling systems in both adjacent track segments. Consequently, a single short circuit at one joint can potentially connect the electrical path of the signals in both directions along the track, leading to interference and faulty signaling logic in these circuits.

Thus, the correct understanding here is that a single short-circuit would impact two track signal circuits, reflecting the interconnected nature of the rail system and the role of insulated joints in maintaining the integrity of electrical isolation and signaling.